1. Field of the Invention
The present invention relates to a security system using a signal transmitted from a wireless communication terminal and a security method using the same, and more specifically to a security system using a signal transmitted from a wireless communication terminal and a security method using the same, in which specific information and numerical information included in the signal transmitted for dialing from the wireless communication terminal are compared with the information that has been stored in advance, and the security certification is performed in accordance with the comparison result.
2. Description of Related Art
As industry has developed, certification in accessing private information has become important, and a high level of security of high fidelity is required.
In general, a certification system or a security system uses a secret number of an account or a card in trading with a financial institution. The secret number generally consists of four numbers only, so the possibility of appropriation of the secret number or duplication of the card is very high. Accordingly, for high-level security, security systems using a fingerprint, an iris, the shape of a vein, DNA or a weight of a human body have been proposed. However, in order to realize such security systems, a significant amount of data must be established about the fingerprint, the iris, the shape of a vein, DNA or the weight of human body, and the information has to be divided in detail to provide the security system of high fidelity without any malfunction.
Moreover, due to the significant amount of data, a large amount of time is consumed in inputting the data and a greater capacity of the security system is required. Furthermore, since a part of body is used as an input method may feel inconvenience, and sanitary problems may be caused by the indirect contact with many other people.
In order to solve such a problem, it is preferable if the security system is implemented with a wireless communication terminal that which is quite popular as of late.
In general, communication using a mobile communication system connects a moving object such as a car, a ship, an aircraft or a train, with a stationary object or another moving object, in order to transmit voice data as well as visual information.
Such a mobile communication service is provided by a Personal Communication Service (hereinbelow, referred to as “PCS”), CT-2, Trunked Radio System (hereinbelow, referred to as a “TRS”), and a wireless communication, which provide rapid and wide-ranging service with upgraded mobility making up for the shortcomings of conventional mobile phones or pagers.
In particular, unlike conventional communication methods where each of the users uses a specific frequency exclusively, TRS communication is a communication method where a great number of subscribers can use a plurality of frequencies together. According to TRS communication, between 150 and 200 subscribers can use a single channel due to efficiency in using the frequencies and high economy. Further, the TRS communication method can provide a variety of services during communication since the channel can be occupied for a certain time period, and provide high performance in communication in providing security compared with conventional wireless communication methods.
The TRS communication method has a shortcoming in that communication time must be restricted as many subscribers use the limited number of frequencies, however, the communication reach is great reaching 20 to 30 kilometers in comparison with a cellular type communication methods, and a small number of repeaters are needed to reduce the investment costs, so the use of the TRS communication method is increasing.
The mobile communication system providing such a wireless communication terminal is illustrated in FIG. 1. As shown in the figure, the mobile communication system is comprised of a repeater 7, a private exchange 3 and a public exchange network 1. The repeater 7 re-transmits the signal transmitted to/from a plurality of terminals 9a to 9n such as a wireless communication terminal or a PCS after amplifying the received signal to a certain level. The private exchange 7 allots the signal transmitted from the repeater 7 to a communication channel such as an inner line or a local line for a certain period of time, performs the transfer of the information about the repeater 7 or the subscribers stored in a subscriber management unit 5, and controls the terminals 9a to 9n and the repeater 7. The public exchange network 1 connects the signal transmitted from the private exchange 3 to a public communication network.
Here, the subscriber management unit 5 manages the information about the terminals 9a to 9n and the users of the terminals 9a to 9n. 
The public exchange network 1 includes an exchange and a mobile telephone exchange station, which connects general subscribers with the terminal users or connects the terminal users with each other.
In the mobile communication system having the above-described construction, the process of communication using the terminals is illustrated in FIG. 2.
FIG. 2 illustrates the flow of the signal, which shows the communication process between the terminal and the private exchange. At first, the terminal is maintained on stand-by mode to receive the control signal from the repeater 7 while the terminal is not used for communication. In such a situation, bilateral communication is not performed between the repeater 7 and terminals 9a to 9n. 
Afterwards, when the power of the terminal is turned on, the terminal searches the nearest repeater which is detected to transmit the strongest possible signal in the location of the terminal, and refers the coverage of the repeater registered in the program of the terminal.
Then, the terminal transmits the registered information of the terminal and the specific information ID of the terminal, which have been registered in the program of the terminal, and the repeater 7 re-transmits the data to the private exchange 3 in which the information of the terminal and the users of the terminal are stored in advance.
The private exchange 3 receives the data, and searches the information about the terminal through the subscriber management unit 5 which stores and manages the information about the terminal, which is ON.
If the information about the terminal is determined to be the terminal managed in the exchange during the searching process, the terminal transmits the data to the repeater to inform that the terminal that it is located within the coverage of the repeater 7, and then the repeater 7 transmits a confirmation message to the terminal.
As described above, in order to communicate with the terminal, each of the terminals transmits specific information of its own to the repeater 7, and the repeater 7 transmits the data to private exchange 3 to secure a communication channel by searching the terminal information in the subscriber management unit 5.